1. Field of the Invention
The present invention relates to an image input apparatus, commonly called a "scanner," and a scanning method which converts an image to electrical signals and inputs those signals into a computer.
2. Description of the Related Art
In a conventional image input apparatus, or "scanner," an image of an original print or photographic film is formed on a CCD linear sensor using an image-forming optical system. The image signal is processed in sequence while scanning by moving the linear sensor within an image forming plane in a direction perpendicular to the array of the pixels in the CCD linear sensor.
In most of these conventional scanners, the positional relationship of the image-forming optical system is fixed. As recognized by the present invention, this fixed positional relationship results in a reduction in the resolution of the processed image due to slippage of the focal point brought about by floating or warping of the original or by fluctuation in the thickness of a slide mount or film holder.
Moreover, in scanners which are equipped with an auto-focus mechanism, there is a problem in that the configuration becomes complex, resulting in higher costs.